Intensity of GFAP immunoreaction. Pseudocolor-intensity maps drawn with MATLAB program. All maps had the same preset color scale that assigned a color to each intensity value, identifying different intensity levels of the GFAP-IR (Müller cells plus astrocytes). Cool colors represent lower intensity levels while warm colors represent higher intensity levels. Although no differences in mean intensity of GFAP-IR were found between naïve (A) and contralateral (B) eyes, differences were found when the comparison was made by the percentage of the retinal area occupied by GFAP+ cells with higher intensity levels. C-D microphotographs were taken from the same retina. They illustrate that OHT-eyes had retinal areas with high (C) and low (D) intensity of GFAP-IR, the later having mainly astrocytes in which only primary processes were detected. GFAP-IR, glial fibrillary acidic protein immunoreaction; OHT, ocular hypertension.